40 hp Johnson has a crack in a intake runner Help

[natestep]

I am looking to buy a boat. It has what I believe to be a 1988 Johnson 40hp VRO. The guy said that he took the boat out and it was running fine. All of a sudden the motor just shut off. He said the motor would turn over but not start. He took the cowl off and saw a small crack on the right side of the intake. I am an automotive mechanic and realize this is probably a vaccum issue. What I dont know is what would have cause this crack. It is about a half inch long on the upper intake runner on the right side of the engine when looking at it from the front. The boat has been sitting for about five years. Any help would be much appriciated. I dont want to make a mistake buying this boat if im gonna hafta replace a power head.

 

[Lil' Blue Rude]

The first thing that comes to mind is it threw a rod. That's the only reason i've heard of them busting like that. Only way to tell for sure would be taking off the reed plates to look down the runner. You would be able to clearly see the crank and rod assembley. 40hp johnsons are good motors and are dang near bullet proof for the most part . If you buy the boat you could pick up a new power head on ebay for a couple hundred and you would have some spare parts off the old motor. It would be an easy swap. Less than an hour if you know what your doing.Thats just my two cents.

 

[natestep]

Thanks for the response. I was afraid of something like that. I have done carbs and diagnostics on the electrical stuff on outboards but never been in one. I looked on ebay and the cheapest one on there now is starting bid $300.00 and about $70.00 for shipping. I made an offer on the boat and I will be able to pay that if he takes the offer. The power head is not that big of a job to change? Does it require any special tools?

 

[crazymanme2]

I agree with Lil' Blue Rude comments.Sounds to me like the oil pump quit working,threw a rod.Never was a fan of oil injection.
No special tools to change power heads.You could pull the plugs to see if a piston is not moving when turned over.

 

[natestep]

If I do wind up with it and I put another power head on it the pump is going. Its not that big of a deal for me to mix the gas and then I know its oiling. Thanks for the replies.

 

[Lil' Blue Rude]

No good vro pumps :x You won't need any special tools to remove the powerhead. If I remeber correctly it's 8 bolts to take the belly pan off, 4bolts bolting through the mid section to the powerhead, and 1 nut in the back that holds the powerhead to the exhaust plate. Pluse the throttle links and the electical plug. No big deal at all.That's the great thing about these motors easy to work on. I bought mine when I was 15, I got it home that night and had it stripped down in about 3hours. If you need any help with it or have any questions let me know. I'm more than willing to help.

 

[natestep]

Thanks LBR, He called back last night and took my offer so I guess I have one to change. I might have some questions during the process. Thanks for the offer.

 

[natestep]

Well back to the drawing board. I got the boat home today and pulled the plugs. Both pistons moving and lots of compression. I dont have a compression guage but it would blow me finger out of the hole. ](*,)

 

[Lil' Blue Rude]

Time to break out the tools. :mrgreen:Start by unbolting the carbs, you should be able to get to the nuts without taking any thing off, there will be two nuts per carb. Then unbolt the reed plate from the front half, should be around 10 or 11 bolts. You won't need to take the four screws out becuse they hold the reed cages to the reed plate. You will then be able to inspect the crank assembley and the front half. move the fly wheel back and forth to see if the top rod has any play at the base. Let me now what you find and if you have any more questions just let me know.
Good Luck, Cody

 

[natestep]

I will do that in the morning. I really appriciate your help on this. I am the lead bidder on a powerhead on Ebay right now. I would like to know what is wrong with this one before I drop that much money on something I dont need if I can fix this one. Once again thanks!

 

[Lil' Blue Rude]

I'm more than happy to help. Hopefully we can figure it out before that auction ends. Like I said let me know what you find when you get that apart.
Cody

 

[natestep]

Well yall, its time for a new powerhead. I tore it down this morning and it was a rod bearing failure. Shavings everywhere, hit the reedbox hard, ruint the crank, bent a rod cap bolt, and punched two holes in the block. Thanks for all the help. The auction ends in the morning so I will let yall know if I win it. Im sure there will be more questions. I did ask and receive a download for a manuel on it from tinboats. I have DSL so im waiting to go steal Mom and Dad's internet to download it. Thats where the shop and all my tools are anyway. Thanks for all yalls help.

 

[Lil' Blue Rude]

Ouch. Well look at the bright side you have some spare electricals now.

 

[natestep]

I won the powerhead. Its a complete fresh water powerhead. It included all the electronics and had a leak down result of 6% and 8% so I think its a fairly low hour unit. Cant wait to get it and hear this thing run. I worked on the boat alot yesterday cleaning it up and gonna go get some new tires for the trailer today. It had sit so long the tires were so bad dry rotted they wouldnt hold air.

 

[natestep]

I got the new powerhead on today and it was a piece of cake. I also changed the impeller and checked it over real good. I took it to the river since the hose was froze up and it turned over a couple times and fired up. Thats a sweet sound. Good water stream and cant wait for it to warm up now so I can go for a ride.

 

[Lil' Blue Rude]

Glad to hear that it all worked out for you. Now it's running, time to make it go fast :lol: